1. Field of the Invention
The invention is in the field of service vehicle hailing, and more particularly through use of a cellular telephone handset.
2. Description of the Prior Art
A dispatch-based taxi fleet comprises a collection of taxis (one type of service vehicle), distributed within some geographic region, and a central dispatch office. Typically, the central dispatch office has an automatic means for tracking the location of each active service vehicle, based for instance on the global positioning system (GPS), or some other suitable radiolocation technology.
A primary function of the central dispatch office is to receive customer pickup requests, match them with available service vehicles, and dispatch the service vehicle to the customer. This is typically done through the following steps:                1. A customer places a conventional telephone call to the central dispatch office, and is connected with a human operator, also called a “telephonist.”        2. The customer supplies the desired pickup address. Sometimes the destination address, and additional information or parameters such as desired characteristics of the service vehicle (e.g., extra large capacity), may be supplied as well.        3. The telephonist identifies a suitable service vehicle, ideally located close to the requested pickup address.        4. The service vehicle is assigned to the customer, and proceeds to the requested pickup location.        5. The telephonist confirms the dispatch of the service vehicle to the customer.        6. Optionally, the telephonist may supply to the customer a reservation or confirmation number, and/or a number identifying the dispatched service vehicle. While not common in the US market, this is typical in the European market. The service vehicle identifier enables the customer to ensure that they are taking the right taxi. The reservation or confirmation number enables the driver to ensure that they are serving the right customer. The reservation or confirmation number also allows the customer to recontact the dispatch office at a later time to check the progress of the dispatched vehicle and/or cancel the dispatch request should the customer's needs change.        7. The telephonist and the customer end their telephone call and the customer waits for pickup by the service vehicle.        8. The service vehicle meets the customer and takes them to the desired location.        
One major cost of operating this system is the labor cost of the telephonist. The telephonist is occupied, by a single caller, from step 1 through step 7 above inclusive. The labor cost of the telephonist, and the associated costs of office space, telephone equipment, etc., place a limit on the size of taxi fleet businesses.
Some attempts have been made to eliminate the telephonist. One solution uses automated speech recognition (ASR) technology to automate the interaction with the customer, deploying this technology in what is referred to as an interactive voice response (IVR) mode. In such a solution, the customer again places a conventional audio telephone call to the dispatch office. However, the call is answered not by a human operator, but by a computer system equipped with ASR and text to speech (TTS) technology. This computer system attempts to perform the function of a human telephonist. The customer is prompted to speak the pickup address. The customer's spoken response, propagated over the conventional telephone system, is then processed by the ASR technology in an attempt to yield the pickup address. The remaining steps are also completed by automatic means, and the service is nominally rendered to the customer as described above. This design is offered commercially now, by Raywood Communications Pty Ltd, of Victoria, Australia, and Sigtec Pty Ltd, of Seaford, Australia.
This prior approach, while in principle offering an advantage over the use of human telephonists, has limitations in practice. One problem is the use of a conventional wireline or wireless audio telephony channel, where the caller's audio is subjected to arbitrary noise, dropouts or other corruptions. This reduces the accuracy of the speech recognition system, sometimes rendering the proposed solution unusable. Another problem is the rigid structure of the computer system, which can accept and respond to only a limited number of predefined commands or inputs, and which must interact with the customer exclusively via audio input and output. All of these present obstacles to the success of this prior solution.
Another potential solution is the use of Short Message Service (SMS) or text messages, sent from a cellular telephone handset. With SMS, modern cellular telephones support the composition of brief text messages (up to 160 characters in length), which may then be transmitted wirelessly to another cellular telephone, or to a suitable computer interface. In such a system the customer composes a text message comprising the address of the desired pickup location. This text message is wirelessly transmitted to a suitable computer system operated by the taxi fleet operator. This computer interprets the address, and assuming it represents a valid pickup location, proceeds to assign a suitable service vehicle to the customer. The computer sends a confirming text message back to the customer, advising of imminent pickup. This design is offered commercially now, by Sigtec Pty Ltd, of Seaford, Australia.
However, this approach also has limitations, for example, the need for the customer to compose the text message containing the pickup address, a maximum text message size of 160 characters, etc.
What is needed, therefore, is an improved dispatch system that can eliminate the costs and inconveniences described above while still providing reliable and convenient customer service.